Inheritance Theory
Biology: AQA GCSE Higher, topic 6.3.4
Theory of Inheritance of Acquired Characteristics
Other theories of evolution proposed that changes in an organism over its lifetime could be passed on to its children. The most famous of these theories was Lamarck's theory of inheritance of acquired characteristics. In giraffes, he argued:
Long necks
- Giraffes have very long necks, which allow them to reach the upper branches of trees to feed (eat).
Early giraffes
- Earlier giraffes had shorter necks and so would have to stretch to reach their food.
Stretching
- Continual stretching resulted in the elongation of giraffe necks within a lifetime.
New characteristic passed on
- Lamarck believed that this newly-acquired characteristic would then be passed on to the next generation.
- Lamarck's theory has since been disproven. Changes that happen in an animal's lifetime are NOT passed on to future generations.
Test yourself on Inheritance Theory
Lamarckian Evolution
Why did Lamarck believe giraffes evolved long necks?
How does the modern scientific understanding of inheritance differ from what Lamarck proposed?
What did Lamarck propose happens to a characteristic gained during an organism's lifetime?